Spinous process fixation implant

ABSTRACT

An implantable spinous process fixation device includes a first plate component having an elongated plate and front and back cross plates extending at right angle to the front and back of the elongated plate, respectively, a top pivoting plate and a bottom pivoting plate. The top and bottom pivoting plates are configured to pivot around an axis perpendicular to the front and back cross plates and the elongate plate has an inner surface facing an inner surface of the top pivoting plate and an inner surface of the bottom pivoting plate.

CROSS REFERENCE TO RELATED CO-PENDING APPLICATIONS

This application claims the benefit of U.S. provisional application Ser.No. 60/750,520 filed Dec. 14th, 2005 and entitled “SPINOUS PROCESSFIXATION IMPLANT’, the contents of which are expressly incorporatedherein by reference.

FIELD OF THE INVENTION

The present invention relates to a system and a method for spinalstabilization through an implant, and more particularly to spinalstabilization through attachment of the implant to the spinous processesalong one or more vertebras.

BACKGROUND OF THE INVENTION

The human spine comprises individual vertebras 30 (segments) that areconnected to each other to form a spinal column 29, shown in FIG. 1.Referring to FIGS. 1B and 1C, each vertebra 30 has a cylindrical bonybody (vertebral body) 32, three winglike projections (two transverseprocesses 33, 35 and one spinous process 34), left and right facetjoints 46, lamina 47, left and right pedicles 48 and a bony arch (neuralarch) 36. The bodies of the vertebrae 32 are stacked one on top of theother and form the strong but flexible spinal column. The neural arches36 are positioned so that the space they enclose forms a tube, i.e., thespinal canal 37. The spinal canal 37 houses and protects the spinal cordand other neural elements. A fluid filled protective membrane, the dura38, covers the contents of the spinal canal. The spinal column isflexible enough to allow the body to twist and bend, but sturdy enoughto support and protect the spinal cord and the other neural elements.The vertebras 30 are separated and cushioned by thin pads of tough,resilient fiber known as inter-vertebral discs 40. Disorders of thespine occur when one or more of the individual vertebras 30 and/or theinter-vertebral discs 40 become abnormal either as a result of diseaseor injury. In these pathologic circumstances, fusion of adjacentvertebral segments may be tried to restore the function of the spine tonormal, achieve stability, protect the neural structures, or to reliefthe patient of discomfort.

Several spinal fixation systems exist for stabilizing the spine so thatbony fusion is achieved. The majority of these fixation systems utilizerods that attach to screws threaded into the vertebral bodies or thepedicles 48, shown in FIG. 3C. In some cases plate fixation systems arealso used to fuse two adjacent vertebral segments. This constructionusually consists of two longitudinal plates that are each placedlaterally to connect two adjacent pedicles of the segments to be fused.This system can be extended along the sides of the spine by connectingtwo adjacent pedicles at a time similar to the concept of a bicyclechain. Current plate fixation systems are basically designed to functionin place of rods with the advantage of allowing intersegmental fixationwithout the need to contour a long rod across multiple segments. Boththe plating systems and the rod systems add bulk along the lateralaspect of the spine limits access to the pars and transverse processesfor decortication and placement of bone graft. In order to avoid thislimitation many surgeons decorticate before placing the rods, therebyincreasing the amount of blood loss and making it more difficult tomaintain a clear operative field. Placing rods or plates lateral to thespine leaves the center of the spinal canal that contains the dura,spinal cords and nerves completely exposed. In situations where problemsdevelop at the junction above or below the fused segments necessitatingadditional fusion, the rod fixation system is difficult to extend tohigher or lower levels that need to be fused. Although there areconnectors and techniques to lengthen the fixation, they tend to bedifficult to use and time consuming.

Accordingly, there is a need for a spinal stabilization device that doesnot add bulk to the lateral aspect of the spine and does not limitaccess to the pars and transverse processes for decortication andplacement of bone graft.

SUMMARY OF THE INVENTION

In general, in one aspect, the invention features an implantableassembly for stabilization of spinous processes, including a first platecomponent, a top pivoting plate and a bottom pivoting plate. The firstplate component includes an elongated plate and front and back crossplates extending at right angle to the front and back of the elongatedplate, respectively. Te top and bottom pivoting plates are configured topivot around an axis perpendicular to the front and back cross plates,and the elongate plate includes an inner surface facing an inner surfaceof the top pivoting plate and an inner surface of the bottom pivotingplate.

Implementations of this aspect of the invention may include one or moreof the following features. The top and bottom pivoting plates areconfigured to be received within a gap formed between the front and backcross plates. The assembly further includes a post member configured topass through concentrically aligned through-bore openings formed in thefront cross plate, the top pivoting plate, the bottom pivoting plate andthe back cross plate. The top and bottom pivoting plates are configuredto pivot around the post member and to set first and second pivot angleswith the elongated plate thereby defining first and second spacesbetween the elongated plate and the top and bottom pivoting plates,respectively. The post member includes a locking element for securingand preventing pivoting of the top and bottom pivoting plates relativeto the elongated plate. The post member may be an elongated bolt and thelocking element may be threads formed at a portion of the bolt,dimensioned to engage inner threads in the back cross platethrough-bore. The post member may be an elongated bolt and the lockingelement may be threads formed at a portion of the bolt, dimensioned toengage a nut after the bolt exits the back cross plate through-bore. Theinner surfaces of the elongated plate, the top and bottom pivotingplates include protrusions configured to engage and frictionally lockthe plates onto first and second spinous processes positioned in thefirst space between the elongated plate and the top pivoting plate andthe second space between the elongated place and the top pivoting plate,respectively. The front and back cross plates are dimensioned to fitbetween the first and second spinous processes and comprise edgessculpted to conform to the shape of the spinous processes. The first andsecond pivot angles comprise values between zero and 180 degrees. Thetop and bottom pivoting plates are pivoted to first and second pivotangles of 90 degrees relative to the elongated plate for sidewiseinsertion of the assembly between the first and second spinousprocesses. The assembly may be assembled prior to or after beingimplanted between the first and second spinous processes. The assemblymay further include an additional locking member for securing the toppivoting plate relative to the elongated plate. The additional lockingmember may be a set screw dimensioned to pass through and engage threadsformed in the inner surface of a second through bore formed in the frontcross plate and to frictionally engage the top pivoting plate. Theassembly may further include a top locking member configured to lock theelongated plate's top end and the top pivoting plate's top end. The toplocking member may be a long bolt configured to be threaded through boltholes formed through the top pivoting plate end, the first spinousprocess and the elongated plate top end. The top locking member may bestaples, cables, sutures, pins or screws. The assembly may furtherinclude a bottom locking member configured to lock the elongated plate'sbottom end and the bottom pivoting plate's bottom end. The bottomlocking member may be a long bolt configured to be threaded through boltholes formed through the bottom pivoting plate bottom end, the secondspinous process and the elongated plate bottom end. The bottom lockingmember may be staples, cables, sutures pins or screws. The protrusionsmay be teeth, spikes, serrations, rough coatings or ridges. The firstplate component, the top and bottom pivoting plates may be made ofstainless steel, titanium, gold, silver, alloys thereof or absorbablematerial. The first plate component, the top and bottom pivoting platesmay have adjustable lengths. Each of the top and bottom pivoting platesmay include a main body and an extending arm. The extending arm may bedetachable from the main body and may be attached to the main body via ahinge.

In general, in another aspect, the invention features a method forstabilizing spinous processes of a spinal column, including providing afirst plate component, a top pivoting plate and a bottom pivoting plateand. The first plate component includes an elongated plate and front andback cross plates extending at right angle to the front and back of theelongated plate, respectively, and engages an inner surface of saidelongated plate with a first lateral surface of a first spinous processand a first lateral surface of a second spinous process. The toppivoting plate is pivoted toward the elongated plate to engage an innersurface of the top pivoting plate with a second lateral surface of thefirst spinous. The second lateral surface of the first spinous processis opposite to the first lateral surface of the first spinous process.The bottom pivoting plate is pivoted toward the elongated plate toengage an inner surface of the bottom pivoting plate with a secondlateral surface of the second spinous process. The second lateralsurface of the second spinous process is opposite to the first lateralsurface of the second spinous process. The top and bottom pivotingplates are configured to pivot around an axis perpendicular to the frontand back cross plates.

Among the advantages of this invention may be one or more of thefollowing. The assembly stabilizes vertebras by attaching plates to thespinous processes of the vertebras. This stabilization device does notadd bulk to the lateral aspect of the spine and does not limit access tothe pars and transverse processes for decortication and placement ofbone graft.

The details of one or more embodiments of the invention are set forth inthe accompanying drawings and description below. Other features, objectsand advantages of the invention will be apparent from the followingdescription of the preferred embodiments, the drawings and from theclaims

BRIEF DESCRIPTION OF THE DRAWINGS

Referring to the figures, wherein like numerals represent like partsthroughout the several views:

FIG. 1A is a side view of the human spinal column;

FIG. 1B is an enlarged view of area A of FIG. 1A;

FIG. 1C is an axial cross-sectional view of a lumbar vertebra;

FIG. 2 is a posterior view of a portion of the spine with a firstembodiment of a spinous process fixation implant according to thepresent invention affixed thereto;

FIG. 3 is a top view of the spine with the spinous process fixationimplant of FIG. 2 affixed thereto;

FIG. 4 is a front side view of the spinous process fixation implant ofFIG. 2;

FIG. 5 is a back side view of the spinous process fixation implant ofFIG. 2;

FIG. 6 is a right side perspective view of the spinous process fixationimplant of FIG. 2;

FIG. 7 is partially exploded right side perspective view of the spinousprocess implant of FIG. 2;

FIG. 8 is a left side perspective view of the spinous process fixationimplant of FIG. 2;

FIG. 9 is a top perspective view of the spinous process fixation implantof FIG. 2;

FIG. 10 is an exploded right side perspective view of the spinousprocess fixation implant of FIG. 2;

FIG. 11 is a front side view of the elongated component 110 of FIG. 2;

FIG. 12 is a back side view of the elongated component of FIG. 2;

FIG. 13 is a front side view of the top pivoting component of FIG. 2;

FIG. 14 is a front side view of the bottom pivoting component of FIG. 2;

FIG. 15 is a front side view of a second embodiment of a spinous processfixation implant according to the present invention, depicting the topand bottom pivoting components in the closed position;

FIG. 16 is a front side view of the spinous process fixation implant ofFIG. 15 with the top and bottom pivoting components in the openposition;

FIG. 17 is a left side perspective view of the spinous process fixationimplant of FIG. 15, depicting the top and bottom pivoting components inthe closed position;

FIG. 18 is a left side perspective view of the spinous process fixationimplant of FIG. 15, depicting the top and bottom pivoting components inthe open position;

FIG. 19 is an exploded left side view of the spinous process fixationimplant of FIG. 15

FIG. 20A is a right side view of the elongated plate component 210 ofFIG. 15;

FIG. 20B is a right side view of the top pivoting component 220 of FIG.15

FIG. 20C is a right side view of the bottom pivoting component 230 ofFIG. 15

FIG. 21 is a front side view of a third embodiment of a spinous processfixation implant according to the present invention, depicting front andback pivoting components in the closed position around the spinousprocesses;

FIG. 22A depicts insertion of the spinous process fixation implant ofFIG. 21 from the side with front and back pivoting components in theopen position;

FIG. 22B depicts pivoting the front and back pivoting components of FIG.21 to close them around the spinous processes;

FIG. 23 is a front side view of the embodiment of a spinous processfixation implant according of FIG. 21, depicting front and back pivotingcomponents in the closed position and locked position around the spinousprocesses;

FIG. 24 is a front side view of a fourth embodiment of a spinous processfixation implant according to the present invention, depicting front top, front bottom and back pivoting components in the closed positionaround the spinous processes;

FIG. 25A is a front side view of the front top pivoting component of thespinous process fixation implant of FIG. 24;

FIG. 25B is a front side view of the front bottom pivoting component ofthe spinous process fixation implant of FIG. 24;

FIG. 25C is a front side view of the back pivoting component of thespinous process fixation implant of FIG. 24;

FIG. 26 is a front side view of the locking component of the spinousprocess fixation implant of FIG. 24;

FIG. 27 is a front side view of a fifth embodiment of a spinous processfixation implant according to the present invention, depicting front andback pivoting components in the closed and locked position around thespinous processes;

FIG. 28 depicts cutting and opening paths A and B around superior andinferior adjacent spinous processes;

FIG. 29 depicts inserting back pivoting component of the spinous processfixation implant of FIG. 27 along path A of FIG. 28; and

FIG. 30 depicts inserting front pivoting component of the spinousprocess fixation implant of FIG. 27 along path B of FIG. 28; and

FIG. 31 is a front side view of a sixth embodiment of a spinous processfixation implant according to the present invention, depicting a singleK-component body.

DETAILED DESCRIPTION OF THE INVENTION

The present invention relates to a system and a method for a spinousprocess fixation implant.

Referring to FIG. 2, FIG. 3, and FIG. 4, a spinous process fixationassembly 100 stabilizes two adjacent vertebras 92, 94 of the human spineby engaging and locking their spinous processes 90 a and 90 b,respectively. Spinous process fixation assembly 100 includes an elongateplate 110 and top and a bottom pivoting plates 120, 130, locatedopposite to plate 110 and configured to form a K-shaped structuretogether with plate 110. Top and bottom pivoting plates 120, 130 pivotaround axis 140 (shown in FIG. 6) independent from each other, formingangles 162, 164 with plate 110, respectively. The pivoting motion ofplates 120, 130 along directions 144 a, 144 b and 146 a, 146 b, movesthem close to or away from the elongated plate 110, as shown in FIG. 4.Elongated plate 110 has a body 112 and front and back cross plates 114,116, extending at right angle to the front of the body 112 and back ofthe body 112, respectively, as shown in FIG. 10, FIG. 11 and FIG. 12.Body 112 has a top end 113 a, a bottom end 113 b, an outer surface 118and an inner surface 117. Axis 140 passes through apertures 152 and 154formed in the centers of the cross plates 114, 116, respectively, asshown in FIG. 11 and FIG. 12. Cross plates 114, 116 extend between thebottom surface and top surface of the adjacent spinous processes 90 a,90 b, respectively and have edges 115 which are rounded and sculpted tocorrespond to the geometry of the spinous processes 90 a, 90 b andlamina around which they will fit once implanted. Cross plates 114, 116are substantially flat, parallel to each other and a gap is formedbetween them sized to hold portions of the top and bottom pivotingplates 120, 130,as shown in FIG. 7.

Referring to FIG. 10, FIG. 13 and FIG. 14, top pivoting plate 120 has amain body 122 with top and bottom ends 123 a, 123 b, respectively andinner 127 and outer surface 128, respectively. An arm 124 extendsdownward from the bottom end 123 b of the body 122 and a side plate 128extends at right angle to the back of the body 122. The arm 124 has anaperture 126 located at the bottom left corner and extends from thefront side to the back side of the arm 124. Similarly, bottom pivotingplate 130 has a main body 132 with top and bottom ends 133 a, 133 b,respectively, and inner and outer surfaces 137, 138 respectively. An arm134 extends upward form the top end 133 a and has an aperture 136 at thetop left corner, extending from the front side to the back side of thearm 134, as shown in FIG. 10, and FIG. 14. A side plate 138 extends atright angle from to the back of the body 132. All edges of plates 110,120, 130 are rounded to prevent damage of the adjacent tissue duringimplantation or spinal movement. Plates 110, 120, 130 are made ofstainless steel, titanium, gold, silver, alloys thereof, or absorbablematerial and may adjustable lengths.

Referring to FIG. 7, a long bolt 180 passes through apertures 152 and154 of the cross plates 114, 116 of the elongated plate 110 and thoughapertures 126 and 136 formed in the top and bottom pivoting plates 120,130, respectively. Bolt 180 has a head 181, a shaft 183 and threads 184formed on the end portion of the shaft 183. Threads 184 engage threadsin the aperture 154 of the back cross plate 116, in order to hold andsecure the three components 110, 120, 130, of the assembly 100 together.In other embodiments, a nut (not shown) is attached at the end of thebolt 180 to hold and secure the three components 110, 120, 130, of theassembly 100 together. In other embodiments bolt 180 is threaded intothe cartilage between the two vertebras to secure the three components110, 120, 130 together and to attach the assembly 100 onto the spine.The inner surfaces 117, 127, 137 of plates 110, 120, 130, respectively,have protrusions 111 that grab and frictionally engage the sides of thespinous processes 90 a, 90 b, as shown in FIG. 3, FIG. 11, FIG. 13 andFIG. 14 . Protrusions 111 may be teeth, serrations, ridges, and otherforms of rough surfaces or coatings that produce rough surfaces. Theposition of pivoting plates 120, 130 relative to each other and relativeto plate 110 is locked with a set screw 182 passing trough the aperture156 formed in the upper right corner of the front cross plate 114.Tightening of the set screw 182 locks the front and back cross plates114, 116 to the pivoting plates 120 and 130. Engaging and locking thespinous process fixation assembly 100 onto spinous processes 90 a, 90 b,prevents the components 110, 120 and 130 from moving sidewise or up anddown toward or away from each other during spinal movement.

The assembled spinous process fixation assembly 100 is implanted intothe patient with the use of instrumentation (not shown) between the twoadjacent spinous processes 90 a, 90 b, as shown in FIG. 2. The crossplates 114, 116 are placed between the spinous processes 90 a, 90 b sothat the body 112 of the elongated plate 110 and the top and bottompivoting plates 120, 130 fall on the lateral sides of the spinousprocesses 90 a, 90 b. One spinous process 90 a lies between the topportion of the body 112 and the top pivoting plate 120, as shown in FIG.3, and the other spinous process 90 b lies between the bottom portion ofthe body 112 and the bottom pivoting plate 130, with their innersurfaces 117, 127, 137 facing the lateral surfaces of the spinousprocesses 90 a, 90 b. On each of the inner surfaces 117, 127, 137 of theplates 110, 120, 130, respectively, the protrusions 111 face toward thelateral surface of the adjacent spinous process. At this point, the topand bottom pivoting plates 120, 130 are pivoted as necessary to providethe desired fit of the plates to the spinous processes. The bolt 180 istightened, clamping the protrusions 111 into the surfaces of the spinousprocesses and locking the three plates relative to each other byengaging the threads of the aperture 154. The protrusions 111 and thethreading of the bolt into aperture 154 of the back cross plate 116frictionally secures the spinous process fixation assembly 100 onto thespinous processes 90 a, 90 b and helps prevent the device from shiftingor slipping.

Referring to FIG. 15, FIG. 16, FIG. 17, FIG. 18, in a second embodimentof the spinous process fixation assembly 200, the top and bottompivoting plates 220, 230 are designed to pivot past each other and toform any angle with the elongated plate 210 between 0 and 180 degrees.In particular, plates 220 and 230 pivot to a 90 degree angle relative toplate 210 and form a sidewise oriented T, shown in FIG. 16 and FIG. 180.The assembly 200 of FIG. 16, with the pivoting plates 220, 230 at a 90degree angle with the plate 110, is inserted sidewise between the topand bottom spinous processes 90 a, 90 b. Once the assembly is inserted,the plates 220 and 230 are pivoted upward and downward, respectively,and are placed at angles relative to the plate 210 necessary to providethe desired fit of the plates to the spinous processes. Sidewiseimplantation of the assembly 200 has the advantage of reduced trauma inthe area between the spinous processes.

In this embodiment the top pivoting plate 220 has a main body 222 withtop and bottom ends 223 a, 223 b, respectively and inner 227 and outersurface 228, respectively, shown in FIG. 19, FIG. 20. Main body 222 hasa width 229 dimensioned to allow plate 220 to pivot past plate 230 whenplaced in the gap 219 between the two cross plates 214, 216 of plate210. An arm 224 extends downward from the bottom end 223 b of the body222. The arm 224 has an aperture 226 located at the center of the bottomend of the arm and extends from the front side to the back side of thearm 224. A protruding annulus 225 surrounds aperture 226 and projectsoutward form the back side of the arm 224. Annulus 225 is dimensioned tofit within aperture 254 of the back cross plate 216. Aperture 226includes inner threads (not shown) extending from the front to the backside of the arm 224. Similarly, bottom pivoting plate 230 has a mainbody 232 with top and bottom ends 233 a, 233 b, respectively, and innerand outer surfaces 237, 238 respectively. Main body 232 has a width 239dimensioned to allow plate 230 to pivot past plate 220 when placed inthe gap 219 between the two cross plates 214, 216 of plate 210. An arm234 extends upward form the top end 233 a and has an aperture 236located at the center of the top end of the arm and extends from thefront side to the back side of the arm 234, as shown in FIG.19 and FIG.20C.

Elongated plate 210, top pivoting plate 220 and bottom pivoting plate230 are assembled together, as shown in FIG. 18. Annulus 225 is insertedin the aperture 254 of the back cross plate 216 and the apertures 252,236, 226 of the front cross plate 214, bottom pivoting plate 230 and toppivoting plate 220, respectively, are aligned. A long bolt 280 isinserted through the aligned apertures and threaded in the inner threadsof the aperture 226. The position of pivoting plates 220, 230 relativeto each other and relative to plate 210 is locked with a set screw 282passing trough the aperture 256 formed in the upper left corner of thefront cross plate 214. Tightening of the set screw 282 locks the frontand back cross plates 214, 216 to the pivoting plates 220 and 230. Onceassembly 200 is implanted into the patient between the two adjacentspinous processes 90 a, 90 b, the assembly is secured and locked inposition, according to the process described above.

Referring to FIG. 21, in a third embodiment the spinous process fixationassembly 300 includes a front S-shaped plate 310 and a mirror image backS-shaped plate 320 connected at their centers via a bolt 380 forming anX-shaped structure. The front S-shaped plate 310 pivots relative to aback S-shaped plate 320 around pivot point 340 and the spinous process90 a of the top vertebra 92 is frictionally engaged between the upperarms of S-plates 310 and 320, while the spinous process 90 b of thebottom vertebra 42 is frictionally engaged between the lower arms ofS-plates 310 and 320. A bolt 380 is threaded through apertures formed inthe centers of the front and back S-plates, as shown in FIG. 21. Theinner surfaces of the upper and lower arms of the S-shaped plates aresculpted to fit the shape of the spinous processes and have protrusionsthat frictionally engage the sides of the spinous processes and togetherwith the bolt 380 securely lock the assembly 300 between the spinousprocesses 90 a, 90 b.

Assembly 300, with the S-shaped plates 310, 320 assembled and orientedhorizontally, as shown in FIG. 22A, is inserted sidewise between the topand bottom spinous processes 90 a, 90 b. Once the assembly is inserted,plates 310 and 320 are pivoted upward and downward, respectively, asshown in FIG. 22B, and they assume a vertical orientation so that theircorresponding inner surfaces surround spinous processes 90 a, 90 b.Sidewise implantation of the assembly 300 has the advantage of reducedtrauma in the area between the spinous processes.

Long bolts 370 may be added to this embodiment to further anchor theassembly 300 on the spinous processes. If they are added, appropriatelysized holes must be drilled laterally through the spinous processesprior to placement of the device. Once the device is in place asdescribed above, one long bolt 370 is threaded through a bolt hole onthe top end of plate 310, through the drilled hole in the spinousprocess 90 a, then out through a bolt hole on top end of plate 320. Asecond long bolt 370 may also be threaded through a bolt hole on thebottom end of plate 310, through the drilled hole in the spinous process90 b, then out through a bolt hole on the bottom end of plate 320.Tightening of bolts 380 and 370 securely locks the assembly 300 aroundspinous processes 90 a, 90 b.

In another embodiment of the spinous process fixation assembly 400,shown in FIG. 24, the front S-shaped plate include a top pivotingcomponent 410, shown in FIG. 25A, and a bottom pivoting component 420,shown in FIG. 25B, forming the top and bottom portions of the S-curve,respectively. The back S-plate 430 is formed as one component S-shapedplate with a curved top portion 432, a bottom curved portion 434 and arounded center 438 having an aperture formed in its center 436, shown inFIG. 25C. The top pivoting component 410 includes an upward extendingcurved portion 412 and a lower rounded end 414 having an aperture 416formed in its center. The bottom pivoting component includes a downwardextending curved portion 422 and an upper rounded end 424 having anaperture 426 formed in its center. The front and back surfaces of therounded end 424, the back surface of the rounded end 414 and the frontsurface of the rounded center 438 have radial extending grooves 425,shown in FIG. 25B and FIG. 25C. Grooves 425 define one-degree arcs, thusallowing the plates 410, 420, 430 to rotate relative to each other byone degree steps. Assembly 400 further includes a block 440 dimensionedto fit between the adjacent spinous processes 90 a, 90 b and having topand bottom edges configured to correspond to the geometry of the spinousprocesses 90 a, 90 b and lamina around which they will fit onceimplanted. Different sized blocks are used to accommodate differentspacings between adjacent spinous processes 90 a, 90 b. The front andback surfaces of block 440 also include grooves 425 around an aperture446 formed n the center of the block. The top pivoting plate 410, bottompivoting plate 420, block 440 and the back plate 430 are arranged sothat their corresponding apertures 416, 426, 446, 436 are aligned and abolt 480 is threaded through these apertures. Once the assembly 400 isinserted, the plates 410 and 420 are pivoted upward and downward,respectively, and are placed so as to surround the spinous processes.The inner surfaces of the upper and lower arms of the S-shaped platesare sculpted to fit the shape of the spinous processes and haveprotrusions that frictionally engage the sides of the spinous processesand together with the bolt 480 securely lock the assembly 400 betweenthe spinous processes 90 a, 90 b.

Long bolts 370 may be also added to this embodiment to further anchorthe assembly 400 on the spinous processes, as was described above.Alternatively, a staple 450 may be placed on the top and bottom openends of the plates 410, 420 and 430, as shown in FIG. 27. In otherembodiments banding, cabling or suturing may be used to attached theends of plates 410, 420 and 430 to the spinous processes. The outersurfaces of the plates 410, 420 and 430 may be rounded, as shown in FIG.24 or straight, a shown in the embodiment 500 of FIG. 27.

Referring to FIG. 28, FIG. 29 and FIG. 30, the process of implanting thespinous process fixation assembly between two adjacent vertebraeincludes the following steps. First an incision is made in the patient'sback and paths A and B are opened along bony planes 95 and throughligaments96 between the adjacent spinous processes 90 a, 90 b. Path B ismirror image of path A about the centered sagittal plane 98. Next, theback component 510 of the assembly of FIG. 27 is inserted along path A,as shown in FIG. 29, and the ends 513 a and 513 b are attached to thespinous processes 90 a, 90 b, respectively. Next, the front component520 is inserted along path B and a bolt is threaded through theapertures 512, 522 formed in the centers of back and front components510, 520, respectively. The front and back components are pivoted aroundthe axis passing through their central apertures 512. 522, so that theirends 513 a, 523 a, 513 b, 523 b surround and close around the spinousprocesses 90 a, 90 b. The ends 513 a, 523 a, and 513 b, 523 b are thenattached to spinous processes 90 a, 90 b, respectively as shown in FIG.30. The ends may be attached with any of the above mentioned methodsincluding frictional engagement of protrusions, long bolts, staples,cabling, banding or suturing. Plates 510, 520 are dimensioned so whenassembled, assembly 500 has a width 535 that covers and protects thespinal cord after laminectomy or facectomy.

In a sixth embodiment, shown in FIG. 31, spinous process fixationassembly 600 includes one K-shaped component having an elongated plate610 and two deformable plates 620, 630 extending upward and downward,respectively, from the center 615 of the elongated plate. A top gap 612is formed between the top portion of the elongated plate 610 and theupward extending plate 620. A bottom gap 614 is formed between thebottom portion of the elongate plate 610 and the downward extendingplate 630. The K-shaped assembly is placed between the adjacent spinousprocesses 90 a, 90 b, as shown in FIG. 31, and a plate 640 is placed inthe center of the assembly 600 on top deformable plates 620, 630. A bolt680 is threaded through apertures formed in the center of plate 640 andthe center 615 of the K-shaped component, as shown in FIG. 31.Tightening of the bolt 680 down applies pressure onto the plate 640,which is transferred to the top and bottom deformable plates 620, 630.Plates 620, 630 move closer to plate 610 and the widths of the top andbottom gaps 612, 614 is reduced, resulting in engaging protrusions 111formed on the inner surfaces of plates 610, 620, 630 with the spinousprocesses 90 a, 90 b and tightening of the plates 620, 630 and 610around the spinous processes 90 a, 90 b. The ends of the plates 620, 630may be further attached to the spinous processes with any of the abovementioned methods including long bolts, staples, cabling, banding orsuturing.

Other embodiments are within the scope of the following claims. Forexample, vertebras 92 and 94 may be any two vertebras, including lumbarL1-L5, thoracic T1-T12, cervical C1-C7 or the sacrum. The fixationassembly 100 may extend along multiple vertebras. The K shaped structuremay be also configured as a mirror image of the structure in FIG. 2,with the pivoting plates 120, 130 located on the left side and theelongated plate 110 located on the right side of the FIG. 2. Theelongated plates 110, 220 and the top and bottom pivoting plates 120,220, and 130, 230 of the embodiments of FIG. 4 and FIG. 15,respectively, may have adjustable lengths. Similarly, S-plates 310, 320of the embodiment of FIG. 21 and plates 410, 420, 430 of the embodimentof FIG. 24 may have adjustable lengths. Similarly, elongated plate 610and deformable plates 620, 630 of the embodiment of FIG. 31 may haveadjustable lengths. The main bodies 122, 132 of pivoting plates 120, 130may be detached from the corresponding extending arms 124, 134. Bodies122, 132 may be attached to the extending arms 124, 134 via hinges (notshown) which allow them to swing open and close for better placementaround the corresponding spinous processes 90 a, 90 b.

Several embodiments of the present invention have been described.Nevertheless, it will be understood that various modifications may bemade without departing from the spirit and scope of the invention.Accordingly, other embodiments are within the scope of the followingclaims.

1. An implantable assembly for stabilization of spinous processes, comprising: a first plate component comprising an elongated plate and front and back cross plates extending at right angle to the front and back of the elongated plate, respectively; a top pivoting plate; a bottom pivoting plate; wherein said top and bottom pivoting plates are configured to pivot around an axis perpendicular to said front and back cross plates; and wherein said elongate plate comprises an inner surface facing an inner surface of the top pivoting plate and an inner surface of the bottom pivoting plate.
 2. The assembly of claim 1 wherein said top and bottom pivoting plates are configured to be received within a gap formed between said front and back cross plates.
 3. The assembly of claim 2 further comprising a post member configured to pass through concentrically aligned through-bore openings formed in said front cross plate, said top pivoting plate, said bottom pivoting plate and said back cross plate.
 4. The assembly of claim 3 wherein said top and bottom pivoting plates are configured to pivot around said post member and to set first and second pivot angles with said elongated plate thereby defining first and second spaces between said elongated plate and said top and bottom pivoting plates, respectively.
 5. The assembly of claim 4 wherein said post member comprises a locking element for securing and preventing pivoting of said top and bottom pivoting plates relative to said elongated plate.
 6. The assembly of claim 5 wherein said post member comprises an elongated bolt and said locking element comprises threads formed at a portion of said bolt, dimensioned to engage inner threads in said back cross plate through-bore.
 7. The assembly of claim 5 wherein said post member comprises an elongated bolt and said locking element comprises threads formed at a portion of said bolt, dimensioned to engage a nut after the bolt exits said back cross plate through-bore.
 8. The assembly of claim 4 wherein said inner surfaces of said elongated plate, said top and bottom pivoting plates comprise protrusions configured to engage and frictionally lock said plates onto first and second spinous processes positioned in said first space between said elongated plate and said top pivoting plate and said second space between said elongated place and said top pivoting plate, respectively.
 9. The assembly of claim 8, wherein said front and back cross plates are dimensioned to fit between said first and second spinous processes and comprise edges sculpted to conform to the shape of said spinous processes.
 10. The assembly of claim 9, wherein said first and second pivot angles comprise values between zero and 180 degrees.
 11. The assembly of claim 10 wherein said top and bottom pivoting plates are pivoted to first and second pivot angles of 90 degrees relative to said elongated plate for sidewise insertion of said assembly between said first and second spinous processes.
 12. The assembly of claim 11 wherein said assembly is assembled prior to being implanted between said first and second spinous processes.
 13. The assembly of claim 11 wherein said assembly is assembled after being implanted between said first and second spinous processes.
 14. The assembly of claim 11 further comprising an additional locking member for securing said top pivoting plate relative to said elongated plate.
 15. The assembly of claim 14 wherein said additional locking member comprises a set screw dimensioned to pass through and engage threads formed in the inner surface of a second through bore formed in said front cross plate and to frictionally engage said top pivoting plate.
 16. The assembly of claim 11 further comprising a top locking member configured to lock said elongated plate's top end and said top pivoting plate's top end.
 17. The assembly of claim 16 wherein said top locking member comprises a long bolt configured to be threaded through bolt holes formed through said top pivoting plate end, said first spinous process and said elongated plate top end.
 18. The assembly of claim 16 wherein said top locking member is selected from a group consisting of staples, cables, sutures, pins and screws.
 19. The assembly of claim 11 further comprising a bottom locking member configured to lock said elongated plate's bottom end and said bottom pivoting plate's bottom end.
 20. The assembly of claim 19 wherein said bottom locking member comprises a long bolt configured to be threaded through bolt holes formed through said bottom pivoting plate bottom end, said second spinous process and said elongated plate bottom end.
 21. The assembly of claim 19 wherein said bottom locking member is selected from a group consisting of staples, cables, sutures, pins and screws.
 22. The assembly of claim 8 wherein said protrusions are selected from a group consisting of teeth, spikes, serrations, rough coatings and ridges.
 23. The assembly of claim 1 wherein said first plate component, said top and bottom pivoting plates comprise material selected from a group consisting of stainless steel, titanium, gold, silver, alloys thereof, and absorbable material.
 24. The assembly of claim 1 wherein said first plate component, said top and bottom pivoting plates comprise adjustable lengths.
 25. The assembly of claim 1 wherein each of said top and bottom pivoting plates comprises a main body and an extending arm.
 26. The assembly of claim 25 wherein said extending arm is detachable from said main body.
 27. The assembly of claim 26 wherein said extending arm is attached to said main body via a hinge.
 28. A method for stabilizing spinous processes of a spinal column, comprising: providing a first plate component comprising an elongated plate and front and back cross plates extending at right angle to the front and back of the elongated plate, respectively, and engaging an inner surface of said elongated plate with a first lateral surface of a first spinous process and a first lateral surface of a second spinous process; providing a top pivoting plate and pivoting said top pivoting plate toward said elongated plate to engage an inner surface of said top pivoting plate with a second lateral surface of said first spinous process, wherein said second lateral surface of said first spinous process is opposite to said first lateral surface of said first spinous process; providing a bottom pivoting plate and pivoting said bottom pivoting plate toward said elongated plate to engage an inner surface of said bottom pivoting plate with a second lateral surface of said second spinous process, wherein said second lateral surface of said second spinous process is opposite to said first lateral surface of said second spinous process; and wherein said top and bottom pivoting plates are configured to pivot around an axis perpendicular to said front and back cross plates.
 29. The method of claim 28 further comprising securing and preventing pivoting of said top and bottom pivoting plates relative to said elongated plate after said engaging of said top pivoting plate inner surface and said bottom pivoting inner surface with said second lateral surfaces of said first and second spinous processes, respectively.
 30. The method of claim 28 wherein said engaging comprises engaging protrusions formed in said elongated plate inner surface, said top pivoting plate inner surface, and said bottom pivoting plate inner surface with said first lateral surfaces of said first and second spinous processes and said second lateral surfaces of said first and second spinous processes, respectively.
 31. The method of claim 28 wherein said top and bottom pivoting plates are configured to be received within a gap formed between said front and back cross plates.
 32. The method of claim 31 further comprising providing a post member and passing said post member through concentrically aligned through-bore openings formed in said front cross plate, said top pivoting plate, said bottom pivoting plate and said back cross plate.
 33. The method of claim 32 wherein said top and bottom pivoting plates are configured to pivot around said post member and to set first and second pivot angles with said elongated plate thereby defining first and second spaces between said elongated plate and said top and bottom pivoting plates, respectively.
 34. The method of claim 33 wherein said post member comprises a locking element for securing and preventing pivoting of said top and bottom pivoting plates relative to said elongated plate.
 35. The method of claim 34 wherein said post member comprises an elongated bolt and said locking element comprises threads formed at a portion of said bolt, dimensioned to engage inner threads in said back cross plate through-bore.
 36. The method of claim 34 wherein said post member comprises an elongated bolt and said locking element comprises threads formed at a portion of said bolt, dimensioned to engage a nut after the bolt exits said back cross plate through-bore.
 37. The method of claim 28, wherein said front and back cross plates are dimensioned to fit between said first and second spinous processes and comprise edges sculpted to conform to the shape of said spinous processes.
 38. The method of claim 33, wherein said first and second pivot angles comprise values between zero and 180 degrees.
 39. The method of claim 38 wherein said top and bottom pivoting plates are pivoted to first and second pivot angles of 90 degrees relative to said elongated plate for sidewise insertion of said top and bottom pivoting plates between said first and second spinous processes.
 40. The method of claim 28 wherein said first plate component and said top and bottom pivoting plates are assembled together prior to being implanted between said first and second spinous processes.
 41. The method of claim 28 wherein said first plate component and said top and bottom pivoting plates are assembled together after being implanted between said first and second spinous processes.
 42. The method of claim 39 further comprising providing an additional locking member for securing said top pivoting plate relative to said elongated plate.
 43. The method of claim 42 wherein said additional locking member comprises a set screw dimensioned to pass through and engage threads formed in the inner surface of a second through bore formed in said front cross plate and to frictionally engage said top pivoting plate.
 44. The method of claim 39 further comprising providing a top locking member and locking said elongated plate's top end and said top pivoting plate's top end.
 45. The method of claim 44 wherein said top locking member comprises a long bolt configured to be threaded through bolt holes formed through said top pivoting plate end, said first spinous process and said elongated plate top end.
 46. The method of claim 44 wherein said top locking member is selected from a group consisting of staples, cables, sutures, pins and screws.
 47. The method of claim 39 further comprising providing a bottom locking member and locking said elongated plate's bottom end and said bottom pivoting plate's bottom end.
 48. The method of claim 47 wherein said bottom locking member comprises a long bolt configured to be threaded through bolt holes formed through said bottom pivoting plate bottom end, said second spinous process and said elongated plate bottom end.
 49. The method of claim 47 wherein said bottom locking member is selected from a group consisting of staples, cables, sutures, pins and screws.
 50. The method of claim 28 wherein said protrusions are selected from a group consisting of teeth, spikes, serrations, rough coatings and ridges.
 51. The method of claim 28 wherein said first plate component, said top and bottom pivoting plates comprise material selected from a group consisting of stainless steel, titanium, gold, silver, alloys thereof, and absorbable material.
 52. The method of claim 28 wherein said first plate component, said top and bottom pivoting plates comprise adjustable lengths.
 53. The method of claim 28 wherein each of said top and bottom pivoting plates comprises a main body and an extending arm.
 54. The method of claim 53 wherein said extending arm is detachable from said main body.
 55. The method of claim 54 wherein said extending arm is attached to said main body via a hinge. 